Type-writing machine.



G. A. MAODERMOTT.

TYPE WRITING MACHINE. nr1.1ou1ox FILED APB. 10,1908.

Patented Nov. 1,1910.

, H w e a I m N m .5 a. m

' Witnesses.- zwp K.

UNITED STATES PATENT OFFICE.

CHARLES A. MACDERMOTT, 0F COLUMBUS, OHIO, ASSIGNOR TO UNDERWOOD TYPE- WRITER COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

TYPE-WRITING MACHINE.

Specification of Letters Patent.

Patented Nov. 1, 1910.

Application filed April 10, 1908. Serial No. 426,199.

To all whom it may concern:

Be it known that I, CHARLES A. MAC- DERMOTT, a citizen of the United States, residing in Columbus, in the county of Franklin and State of Ohio, have invented certain new and useful Improvements in Type-VVriting Machines, of which the following is a specification.

This invention relates to accent-key or silent-key mechanism for typewriting machines, in which a ribbon is caused to vibrate at the type strokes to cover and uncover the printing oint.

The prlncipal object of the invention is to provide simple, effective and inexpensive means for this purpose, which may readily be applied to existing machines.

improvements are illustrated in connectlon with the well known Underwood typewriting machine, in which type bars are caused by keys to swing upwardly and rearwardly to the printing point, and also to operate a universal bar; the latter vibrating a ribbon to cover the printing point, and also operating a carriage escapement mechanism includin a detent-dog and a feeding-dog. The fee ing dog is normally in engagemen with a tooth of the carriage escapement,

wheel, but the movement of the universal bar causes it to escape from said wheel to skip past atooth thereof, so that u on the return movement of the universal ar, the wheel and hence the carriage may advance a space under the tension of the usual carriage driving spring. Accordin to my improvements the accent or silent ey is provided with means to silence said feeding dog, so that it will not ski past an escapement tooth, whereb feeding of the carriage is prevented upon tile operation of said key. This permits an ordinary type to be printed above or below the accent impression on the paper. The feeding dog silencer is conveniently made in the form of an arm extending up from a rock shaft, the latter having also a forwardly projecting arm to engage the lever on which the accent key is carried. When said key is depressed to cause the accent type to print, the dog silencer is rocked into the path of the dog.

In the accompanying drawings, Figure 1 is a rearview of the escapement mechanism of an Underwood typewritin machine embodying my improvements; t e parts being shown in normal positions. Fig. 2 is a sectional side elevation of a portion of the mechanism, showing the parts in normal positions. Fig. 3 is a sectional side elevation of the type mechanism, universal bar, ribb on vibrator, carriage-feeding devices and silent key mechanism, the silent key being shown in its depressed position. Fig. 4 is a rear view showing the normal operation of the feeding dog, when an ordinary type key is depressed.

The ordinary type keys 1 are connected by levers 2 to type bars in the usual manner in said Underwood machine. One of the type bars 3 carries an accent type 4, and is connected by levers 5, 6 to a key 7, whereby the type is caused to strike rearwardly against a platen 8. A universal bar 9 operated by heels 10 on all the type bars, is connected to a horizontal frame 11, the latter hinged at 12 upon upright rock arms 13. The universal bar is driven backwardl at every type bar stroke, and then returned by a spring 14. It carries an actuator 15 for a lever 16, which thrusts up a slide 17 which carries a ribbon 18 in front of the platen 8, so that the type may strike through the ribbon upon the platen. A detent dog 19 is mounted upon a carrier 20, which is pivoted at 21 to vibrate rearwardly and forwardly. The rearward motion is effected by the universal bar during the printing stroke of the type, the universal bar having a contact 22 for this purpose. The do 19 is normally out of engagement with t e teeth 23 of an escapement wheel 24, which is connected to a pinion 25 in mesh with a rack 26.

- The latter is mounted upon a carriage driven by the usual spring barrel, not shown. Also mounted upon the rocker 20 is a feedingor escapement dog 27, which normally restralns the escapement wheel 24, as at Figs. 1 and 2. As so far described, the parts are in common use upon said Underwood machine.

When the key 7 is depressed, the lever 6 is carried down and the lever 5 is swung forward to the Fig. 3 position, thereby swinging the type bar 3 up to print. The heel 10 on the type-bar pushes back a universal bar 9 together with the frame 11 which carries the same, thereby throwing the ribbon up to print. At the same time the detent dog 19 1s swung about the pivot 21 into engagement with the adjacent tooth 23 of the escapement wheel, and the s acing dog 27 is swung back therefrom, as atd ig. 3, and a spring 28, Fig.

1, pulls the dog past the escapement tooth 23, as at Fig. 4. Upon the relief of pressure from the key 7, the parts return to normal positions, the detent dog 19 swinging for- Wardly away from the wheel 24, as at Fig. 2, and the feeding dog 27, which now occupies the next notch in the wheel, swinging into position to arrest the succeeding tooth 23 of the wheel.

According to my present impro vcments an intercepter or stop 29, in the form of a tooth carried upon the upper end of a rock arm 30, is caused by the key 7 to move into the path of the feeding dog 27 to prevent the latter from turning upon its pivot 31, so that said dog cannot escape into the next notch of the wheel. The arm 30 is fixed upon a rock shaft 32 and an arm 33 extends forwardly and downwardly from the latter, and has a hook 34 to catch under the silent or accent key lever 6. The stop 29 swings into effective position before the universal bar 11 moves back sufliciently to disenga e the escapement dog 27 from the wheel, so that upon such disengagement the spring 28 is prevented from swin ing the dog past the tooth 23 of the wheeI. Upon relief of the key from pressure, the universal bar frame 11 returns forwardly to normal position to rengage the feeding dog 27 with the same tooth of the escapement wheel, before the sto 29 swings back out of the path of said fee ing dog, so that no feeding movement of the paper carriage takes place. Hence accents may be readily written over or under any desired letters by simply striking and releasing the accent key before striking the type key.

Having thus described my invention, I claim:

1. In a typewriting machine having typeoperating keys, a carriage, a rack therefor, and a carriage-feeding mechanism, including a feeding dog operated by the keys and having a spring to cause itto pass a rack tooth at the movement of said carriage feeding mechanism, the combination with a typeoperating key, of means operated thereby to prevent said feeding do rom being caused y said spring to pass t e rack tooth at the movement of said carriage-feeding mechanism.

2. In a typewriting machine having ty eoperating keys, a carriage, a rack there or, and a carriage-feeding mechanism, including a feeding d-og operated by the keys and having a spring to cause it to pass a rack tooth at the movement of said carriage feeding mechanism, the combination wit-h a typeoperating key, of means operated. thereby to prevent said feeding dog from being caused by said spring to pass the rack tooth at the movement of said carriage-feeding mechanism, said preventing means including a stop normally out of the path of the dog, and means being operated by said key to project said stop into the path of the dog.

3. In a typewriting machine having typeoperating keys, the combination of a carriage-feeding mechanism, including a feeding dog operated by the keys, and a spring to vibrate said dog past an escapement tooth, a typeoperating key, and means operated by said key to silence said feeding dog; said silencing means including a stop normally out ofthe path of the dog, and means operated by said key to projectsaid stop into the path of the dog to prevent the latter from being vibrated by said spring past an escapement tooth; said stop provided upon the end of a rock arm which is connected to said key.

4:. In a typewriting machine having typeoperating keys and a carriagefeeding mechanism, including a feeding dog operated by the keys, the combination with a type-operating key, of means operated thereby to silence said feeding dog, said silencing means including a stop normally out of the path of the dog, and means operated by said key to project said stop into the path of the dog to prevent the latter from vibrating past an escapement tooth; said stop provided upon the end of a rock arm which is connected to said key; said rock arm mount ed upon a rock shaft, and an arm extending from said rock shaft to engage a lever on which the key is mounted.

5. In a typewriting machine, the combination with a carriage, a rack therefor, typeoperating keys, a universal bar operated by all the keys, a ribbon-vibrating mechanism operated by said universal bar, a carriagefeeding mechanism also operated by said universal bar and including a feeding dog operated by the keys and having a spring to cause it to pass a rack tooth at the movement of said carriage-feeding mechanism, and means operated by one of said keys to prevent said feeding dog from being caused by said spring to escape past the rack tooth at the movement of said carriage feeding mechanism.

0'. A. MAGDERMOTT.

Witnesses:

MYRON R. WARE, MARY MURPHY. 

